High-pressure pump for a fuel injection device of an internal combustion engine

ABSTRACT

The present invention relates to a high-pressure pump for a fuel injection device of an internal combustion engine, with a pump housing, with at least one work chamber disposed in the pump housing functionally between an inlet region and a supply region. A working element is movably disposed in the work chamber, and a pump shaft is provided in the pump housing by means of which the working element can be driven. In order to obtain a shortened structural length, and an extended service life of the pump, a provision is made that the pump housing can be fastened to a wall of a motor housing of the internal combustion engine, wherein the pump shaft can be radially supported against a shaft of the internal combustion engine, which shaft is supported in the motor housing.

The invention relates to a pump, in particular a high-pressure pump fora fuel injection device of an internal combustion engine;

PRIOR ART

DE 44 19 927 A1 has disclosed a high-pressure pump for fuel embodied asa piston pump, and a piston/cylinder unit, which contains a workchamber, disposed in the pump housing of this high-pressure pump, and apump shaft for driving the piston/cylinder unit is supported in thispump housing. The pump shaft is supported in its center and, on itscantilevered drive-side end, supports a cam which is used to act on thepiston/cylinder unit. In order to drive the pump shaft, a drive gear isfastened to its end protruding from the pump housing.

The support of the pump shaft in the pump housing results in arelatively large structural length of the pump, which consequently has arelatively large space requirement. In addition, a relatively costlydrive connection from a motor shaft to the drive gear is required, whichlikewise requires a certain amount of installation space in the enginecompartment. Furthermore, large bearing loads are produced, which leadto an increased wear and to a reduced service life since the effectivebearing length is relatively small compared to the length of thedrive-side end of the pump shaft protruding from the bearing.

DE 42 17 910 A1 has disclosed a hydraulic pump driven by an internalcombustion engine, which is disposed in a cavity in a cylinder headwall. An end of a cam shaft, on which a cam is non-rotatably disposed,which drives a piston of a pump element, extends into this cavitythrough an opening in the cylinder head wall. After the insertion of thepump element and the attachment of the cam to the cam shaft end, thecavity in the cylinder head wall is closed by means of a cap.

This known pump, which is used as a lubricant pump, does indeed have arelatively short structural length, but cannot be produced independentlyof the internal combustion engine. Furthermore, the function of thisknown pump and of its individual pump elements can only be tested afterinstallation into the cylinder head wall of the engine.

ADVANTAGES OF THE INVENTION

The pump according to the invention, has the advantage over the priorart that through the non-rotatable support of the pump shaft on a shaftof the drive motor, no bearings are needed for the pump shaft in thepump housing so that a shortened structural length of the pump isproduced. Moreover, the elimination of the bearing of the pump shaft inthe pump housing results in an increased service life.

Furthermore, the pump according to the invention can be manufactured asa separate subassembly and can be tested as to its functionindependently of the internal combustion engine. In transport andstorage, in order to prevent uncontrolled movements of the movable pumpelements and therefore to prevent damage and problems in the subsequentinstallation, in a preferred exemplary embodiment of the invention, atransport securing device is provided for the pump shaft, whichpreferably has two securing means spaced apart from each other.

It is particularly advantageous if the passage of the pump shaft out ofthe pump housing is sealed since the pump interior is thus protectedfrom impurities during storage, transport, and installation.

In order to be able to compensate for a radial play in the bearing ofthe shaft of the internal combustion engine without influencing thetightness of the pump, in an advantageous embodiment of the invention,the provision is made that the passage of the pump shaft out of the pumphousing is sealed by means of an axial shaft seal in which two smoothfaces are pressed tightly against each other. As a result, a perfectseal can be assured, even with an eccentric motion of the sealing facesin relation to each other.

A particularly non-problematic installation of the pump is produced ifthe pump shaft has a drive-side bearing pin which can be slid into acorresponding axial bore in the shaft of the internal combustion engine.This embodiment also permits the particularly simple connection of anauxiliary drive, which is necessary for a test operation of the pump fortesting purposes.

Advantageous improvements and updates of the piston pump disclosed arepossible by means of the measures taken hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the invention are shown in a simplified form inthe drawings and will be explained in more detail in the subsequentdescription.

FIG. 1 shows a section through a pump according to a first exemplaryembodiment of the invention,

FIG. 2a shows a section through the drive-side end of a shaft of aninternal combustion engine for use with a pump according to theinvention.

FIG. 2b shows a side view, rotated by 90°, of the end of the shaftaccording to FIG. 2a,

FIG. 3 shows a side view of a pump shaft for the pump according to FIG.1,

FIG. 4 shows a side view of a pump shaft for a pump according to asecond exemplary embodiment of the invention, and

FIG. 5 shows a section through a pump according to the second exemplaryembodiment of the invention.

Parts that correspond to one another are provided with the samereference numerals in the different Figs. of the drawings.

DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

As shown in FIG. 1, a pump according to the invention includes a pumphousing 10 with one or more containing regions 11 each for a pumpelement 12, and a containing region 13 in which a pump shaft 14 isdisposed with its drive-side end formed as a cam 31. The containingregion 13 for the drive-side end of the pump shaft 14, together withsections of the containing region(s) 11 oriented toward it, constitutesan inlet region 15 for a medium to be supplied at a relatively lowpressure, in particular for fuel at precompression. By way of an inletline, not shown, the inlet region 15 is connected to a low-pressureinlet connection, not shown, on the pump housing 10.

As a working element, the pump element 12 includes a piston 16, which isguided so that it can move in a piston guide 17. The piston guide 17 isinserted into a securing part 18, which holds the pump element 12 in thecontaining region 11 of the pump housing 10. On the outer circumferenceof the securing part 18, in the region of its inner end 9, a seal 19 isprovided, which seals the inlet region 15 in relation to a supply region20, in which the medium to be supplied is pumped with relatively highpressure, in particular with high pressure, and this supply regionencompasses the securing part 18 in the region of outlet bores 21provided in the securing part 18. By way of a line, not shown, thesupply region 20 is connected to a high-pressure outlet connection, notshown, on the pump housing 10. The supply region 20 is sealed inrelation to the outside by means of a seal 22 between the securing part18 and the inner housing wall that encloses the containing region 11 forthe pump element 12.

The piston 16 has an axial inlet conduit 23, which opens out at the endof the piston 16 disposed in the piston guide 17 and is connected to theinlet region 15 by way of a laterally extending inlet bore 24 in the endof the piston 16 protruding from the piston guide 17. At the mouth ofthe axial inlet conduit 23, the piston 16 has an inlet valve 25 and thusdefines a work chamber 26 in the piston guide 17 and this chamber can beclosed in relation to a high-pressure outlet region 28 by an outletvalve 27. The high-pressure outlet region 28 is connected to the supplyregion 20 by way of the outlet bores 21.

The inlet valve 25 is embodied so that it opens during the intake strokeof the piston 16, i.e. when the piston is moving out of the piston guide17, so that during the intake stroke, medium to be supplied can flowfrom the inlet region 15, through the inlet bore 24, the inlet conduit23, and the open inlet valve 25, into the work chamber 26. During thesupply stroke, i.e. when the piston 16 is moving into the piston guide17, the inlet valve 25 closes so that the medium enclosed in the workchamber 26 is put under pressure. As soon as the pressure in the workchamber 26 achieves a high pressure predetermined by the outlet valve27, this valve opens and the high-pressure medium to be supplied can bepumped through the open outlet valve 27, the high-pressure outlet region28, the outlet bores 21, and into the supply region 20, from which itflows through the line, not shown, to the high-pressure outletconnection on the pump housing 10.

A slide shoe 29 is connected to the free end of the piston 16 protrudingfrom the piston guide 17, and with it, the piston 16 is supported by wayof a stroke ring 30 that is rotatably supported on a cam 31 of the pumpshaft 14, which cam is used as a crank element, so that the piston 16can be driven by the pump shaft 14. In order to hold the piston 16 incontact with the stroke ring 30 by way of the slide shoe 29 during theintake stroke of the piston 16, a spring 32 is provided, which issupported with its one end against the slide shoe 29 and with its otherend against the securing part 18.

As can be seen particularly well in FIG. 3, the pump shaft 14 has asealing collar 33, which on the end remote from the cam 31, is adjoinedby a bearing pin 34 that has a reduced diameter in relation to thesealing collar 33. On the shoulder 35 formed between the bearing pin 34and the sealing collar 33, catch lugs 36 are provided that are disposeddiametrically opposite each other with regard to the pump shaft axis A.Between the sealing collar 33 and the cam 31, a circumferential securingpiece 37 is provided, whose outer diameter is greater than that of thesealing collar 33. An auxiliary pin 38 is connected to the free end faceof the cam 31 and is aligned coaxial to the bearing pin 34.

As shown in FIG. 1, the pump shaft 14 is inserted into the pump housing10 so that its auxiliary pin 38 travels with radial play in an auxiliarybore 39 in an inner housing wall 10 a provided in the pump housing 10,while the sealing collar 33 rests in the region of a through opening 40of the pump housing 10, which opening is encompassed by a centeringcollar 41 extending axially with regard to the pump shaft axis A. Inthis connection, the centering collar 41 and the auxiliary bore 39 arealigned coaxially to each other.

A radial shaft seal 43 is inserted in a sealed fashion into the throughopening 40 and its inner diameter is greater than the outer diameter ofthe sealing collar 33. A support face 42 is provided on the innerdiameter of the radial shaft seal 43. To seal the inlet region 15 or thecontaining region 13 for the cam 31 of the pump shaft 14, there is asealing lip 44 in the radial shaft seal 43 whose inner diameter issmaller than the outer diameter of the sealing collar 33. Consequently,the sealing lip 44 is deformed by the sealing collar 33 and restsagainst it in a sealed fashion. In lieu of the sealing lip 44, a groovedring or the like can also be used, for example.

In the storage and transport of the pump, i.e. of the independentsubassembly comprised of the pump housing 10, pump element 12, pumpshaft 14, and radial shaft seal 43, the pump shaft 14 is pressed by thespring(s) 32 and held with its sealing collar 33 against the supportface 42 provided on the radial shaft seal 43 and is held with theauxiliary pin 38 against the inner wall of the auxiliary bore 39. Thesealing lip 44 of the radial shaft seal 43 can only be deformed by halfthe diameter difference between the inner diameter of the support face42 and the outer diameter of the sealing collar 33. This diameterdifference is laid out so that a constant deformation of the sealing lip44 is prevented. The inner diameter of the sealing lip 44 is suitablychosen so that the sealing lip 44 seals the interior of the pump againstdust and dirt, even when it is deformed in the manner described duringtransport and storage. The radial shaft seal 43 is formed and thesealing lip 44 is incorporated so that the pump shaft 14 comes to restagainst the support face 42 before the sealing lip 44 can be damaged bycrushing.

The sealing collar 33 and the support face 42 of the radial shaft seal43, together with the auxiliary pin 38 and the auxiliary bore 39,thereby constitute a transport securing device for the pump shaft 14 inthe pump housing 14, which holds the pump shaft 14 essentially in itslater operating position in the pump housing 10 when the pump is notattached to the motor housing 45′. In this connection, it isadvantageous that the support face 42, which constitutes a firstsecuring means, and the auxiliary bore 39, which constitutes a secondsecuring means, are spaced axially apart from each other so that thepump shaft 14 cannot tilt in the pump housing 10. In this way, thepiston(s) 16 can in particular be prevented from being pulled too farout of the associated piston guide(s) 17, which can result in problemsupon installation of the pump, particularly in damage to the pistons 16when sliding back in.

In lieu of the auxiliary bore 39, an auxiliary pin or the like can alsobe provided as a second securing means on the inner wall of the pumphousing 10. In this instance, a corresponding auxiliary bore or the likewould then have to be disposed in or on the cam 31.

In addition, during transport and storage, the securing piece 37 on thepump shaft 14, together with the radial shaft seal 43, is used to securethe pump shaft against falling out.

In order to mount the pump—i.e. the independent subassembly comprised ofthe pump housing 10, pump element 12, pump shaft 14, and radial shaftseal 43—to a wall 45 of an internal combustion engine and thereby tobring the pump shaft 14 into engagement with a driven shaft 46 which issupported in a bore 47 a of the internal combustion engine, e.g. with acam shaft, first the bearing pin 34 of the pump shaft 14 is slid into anaxial bearing bore 47, in particular embodied as a fitted bore, in theshaft 46 and then, the centering collar 41 is slid into a receiving bore48 coaxial to the shaft 46 of the internal combustion engine. In thecourse of this, the catch lugs 36 on the shoulder 35 of the pump shaft14 enter into a groove 49 on the end face of the shaft 46, which grooveacts as a catch recess and is provided in an end-face collar 50, asparticularly shown in FIGS. 2a and 2 b. The pump shaft 14 isconsequently supported radially by means of the insertion of the bearingpin 34 of the pump shaft 14 into the bearing bore 47 of the shaft 46 andis supported in the shaft 46 of the internal combustion engine fixedagainst relative rotation by means of the interlocking of the catch lug36 with the groove 49.

The radial support of the pump shaft 14 against the shaft 46 of theinternal combustion engine can also be produced in the reverse manner,with a bearing pin on the shaft 46 and a bearing bore in the pump shaft14. It is furthermore possible to respectively provide both the shaft 46of the internal combustion engine and the pump shaft 14 with a bearingbore and to use a bearing pin that is inserted into both bearing boresin order to support the pump shaft 14 against the shaft 46 of theinternal combustion engine. Parts that protrude well beyond the pumphousing 10 or the motor housing 45′ and can be easily damagedparticularly during transport can therefore be avoided, particularly onboth the as yet unmounted pump and the internal combustion engine.

The axial support of the pump shaft 14 can be carried out in almost anyarbitrary manner since only very low bearing forces have to be absorbedhere. For example, the pump shaft 14 with the auxiliary pin 38 can besupported against the bottom of the auxiliary bore 39 or can besupported with the end face of the cam 31 directly against an opposinginner wall of the pump housing 10 or can be supported against this wallby way of the stroke ring 30. In the other axial direction, the axialsupport of the pump shaft 14 can be carried out for example by thesupport of the catch lugs 36 against the shaft 46 of the internalcombustion engine or by the support of the securing piece 37 against thesupport ring 44.

In the receiving bore 48, a leakage chamber is formed for medium to besupplied, in particular fuel, leaking from the inlet region 15 throughthe radial shaft seal 43 and this chamber is sealed in relation to theouter environment by means of a sealing ring 52 employed on the outercircumference face of the centering collar 41 and is sealed in relationto the shaft 46 and therefore in relation to lubrication oil from itsshaft bearing by means of a lip seal 51. This leakage chamber isevacuated, for example by way of a bore 48′ in the pump housing 10,which can be connected in a manner not shown in detail to an intake tubeof the internal combustion engine if the medium to be supplied is fuel.In lieu of the bore 48′ in the pump housing 10, a bore 48″ can also beprovided in the motor housing 45′, as shown in FIG. 5.

By means of a continual evacuation of the leakage chamber, the lip seal51, which is designed to produce a seal in relation to lubrication oil,is protected from damaging effects of the medium to be supplied, inparticular fuel. This permits the service life of the lip seal 51 to beextended.

Since the receiving bore 48 in the wall 45 of the internal combustionengine is aligned coaxial to the driven shaft 46 and since the centeringcollar 41 is likewise aligned coaxial or concentric to the auxiliarybore 39, the pump shaft 14—which is supported with its bearing pin 34 inthe bearing bore 47 of the shaft 46, which bore is embodied as a fittedbore—is also aligned with its auxiliary pin 38 coaxial to the auxiliarybore 39 and with its support collar 33 coaxial to the radial shaft seal43. Since furthermore, the outer diameter of the auxiliary pin 38 issmaller than the inner diameter of the auxiliary bore 39 and since theouter diameter of the sealing collar 33 is smaller than the diameter ofthe support face 42 on the radial shaft seal 43, during operation, i.e.when the pump shaft 14 is driven by the internal combustion engine byway of the shaft 46—preferably the camshaft, the pump shaft 14 runsfreely in the pump housing 10 without a separate radial support in itand without touching anywhere.

The subassembly comprised of the pump housing 10, pump element 12, pumpshaft 14, and radial shaft seal 43, which is connected to the wall 45 ofthe motor housing 45′ of the internal combustion engine, can be fastenedto the wall 45 of the engine, for example, by means of screws 53 onlyone of which is shown.

In lieu of the described pump shaft 14 with the catch lugs 36, a pumpshaft 14′ can also be used which in the bearing pin 34 adjacent to thesealing collar 33, has a lateral bore 54 into which a catch pin 55 isinserted, as shown in FIG. 5 in connection with a second exemplaryembodiment of the invention, and this catch pin 55 extends beyond theouter circumference of the bearing pin 34 to the point that it can bebrought into catching contact with the grooves 49 on the shaft 46 of theinternal combustion engine.

As FIG. 5 shows, the second exemplary embodiment of the pump accordingto the invention includes a pump housing 10 in which one or a number ofpump elements 12 and a pump shaft 14′ are disposed. The design and thedisposition of the pump element 12 corresponds to the design describedin conjunction with FIG. 1. The pump shaft 14′ differs from the pumpshaft described in conjunction with FIGS. 1 and 3 only by means of thediffering embodiment of the catch means for the rotationally fixedsupport against the shaft 46 of the internal combustion engine. In lieuof the radial shaft seal 43 provided in the pump according to FIG. 1,however, an axial shaft seal 56 is provided in the pump shown in FIG. 5in order to seal off the inlet region 15 in relation to the receivingbore 48 in the wall 45 of the internal combustion engine.

The axial shaft seal 56 includes a catch 57 press-fitted onto thesealing collar 33 and, adjacent to the securing piece 37, a spring 58and a pressing ring 59 are inserted into this catch on the side of thespring 58 remote from the securing piece 37. In addition, a sealing ring60 is disposed between the pressing ring 59 and the sealing collar 33and seals the pressing ring 59 in relation to the sealing collar 33 sothat the pressing ring 59 can move in the axial direction for thepurpose of tolerance compensation.

A slide ring 62 is inserted into an axial extension 61 of the centeringcollar 41 and supports a sealing ring 63 on its outer circumference. Adisk 64, which is fastened to the extension 61 of the centering collar41, for example by means of crimping, holds the slide ring 62 togetherwith the sealing ring 63 in the containing region of the extension 61 ofthe centering collar 41.

In the assembly of the pump according to FIG. 5, first the catch 57, thespring 58, the sealing ring 60, and the pressing ring 59 are mounted inthis order on the sealing collar 33 of the pump shaft 14′. Then thecatch pin 55 is inserted into the lateral bore 54. Since the length ofthe catch pin 55 is greater than the outer diameter of the sealingcollar 33 or is greater than the inner diameter of the pressing ring 59,the catch pin 55 secures the parts of the axial shaft seal 56 disposedon the pump shaft 14′ against the sealing collar 33 and is consequentlyused to secure them against falling out, in particular for the pressingring 59 as long as it is not yet resting against the slide ring 62.

As soon as the pump shaft 14′ is inserted into the pump housing 10 andthe parts of the axial shaft seal 56 secured in the axial extension 61of the centering collar 41 are mounted, the pressing ring 59 is pressedby the spring 58 with its end face 65 remote from the spring 58, whichend constitutes a radial sealing face disposed crosswise to the pumpshaft axis A, against an end face on the slide ring 62, which representsa slide face 66 that is used as a sealing face. The force of the spring58, which is disposed between the pressing ring 59 and the securingpiece 37, is supported against the pump housing 10 by way of thesecuring piece 37, the cam 31, and the auxiliary pin 38.

In this connection, the axial shaft seal 56 functions as a firstsecuring means of the transport securing device while the disk 64 thatholds the slide ring 62 in the extension 61 of the centering collar 41is used to secure it against falling out during transport and storage ofthe pump.

In order to supply a low-friction axial slide bearing for the pump shaft14′ during operation of the pump, a disk 67 is inserted into theauxiliary bore 39, which supports the auxiliary pin 38 in the axialdirection and is preferably made of a low-friction material, inparticular of a slide bearing material.

The use of the above-described axial shaft seal 56 in the pump accordingto the invention has the advantage that a possible radial play of theshaft 46 of the internal combustion engine, which leads to an eccentricrotation of the pump shaft axis A and therefore to an eccentric rotationof the pressing ring 59, has no influence on the sealing of the pumpsince the sealing surfaces resting against each other are smooth and aredisposed perpendicular to the desired course of the pump shaft axis A. Atilting of the pressing ring 59 in relation to the sealing collar 33 dueto the radial play of the shaft 46 of the internal combustion engine iscompensated for in this connection by means of the spring 58 and thesealing ring 60.

The pump according to the invention, which has been described by way ofexample in conjunction with radial piston pumps with one pump element 12or a number of pump elements 12, preferably three disposed in a starpattern, can also be embodied as an axial piston pump. Furthermore, itis also possible to embody the pump according to the invention, in whichthe pump shaft 14, 14′ is inserted in a sealed fashion into the pumphousing 10 without a separate bearing in this housing and can besupported in a drive shaft radially and in such a way that it is fixedagainst relative rotation, as an internal gear pump or the like. In aparticularly advantageous manner, the invention can be used in all pumptypes in which one or a number of working elements are intended to bedriven by way of a cam of a pump shaft.

In particular, the pump according to the invention has the advantagethat it can be manufactured as a separate subassembly, independently ofother parts and can be tested as a completely preassembled, alreadysealed subassembly directly at the manufacturer. As a result, the pumpoperation in particular, i.e. both the functioning of the individualpump elements 12 and their cooperation with the pump shaft 14, 14′ aswell as the tightness, can also be fully tested. A further advantage iscomprised in that with the subsequent installation in the final positionof use, i.e. on an internal combustion engine, no installation dirt canpenetrate into the pump. Furthermore, the elimination of the bearing ofthe pump shaft 14, 14′ in the pump housing 10 extends the service lifeof the pump.

The transport securing device provided in the pump according to theinvention significantly facilitates the subsequent installation of thepump on the motor housing 45′ since the pump shaft 14, 14′ and thereforealso the bearing pin 34 are secured essentially in the operatingposition provided.

In a particularly reliable manner, the use of an axial shaft sealfurthermore permits a sealing of the pump independent of tolerances ofthe shaft 46 of the internal combustion engine, in particularindependent of its radial play.

Dimensionally stable, fuel resistant materials that are matched to eachother in the best way with regard to friction and wear can be used asmaterials for the pressing ring 59 and the slide ring 62. The spring 58provides for a uniform and constant surface pressure, which is largelyindependent of measurement tolerances and wear, between the surfaces ofthe pressing ring 59 and the slide ring 62 sliding against each other,i.e. between the end face 65 and the slide face 66.

In the exemplary embodiment shown in FIG. 1, the support face 42 isprovided indirectly against the pump housing 10 by way of the radialshaft seal 43. However, it is also possible, for example, to match theouter diameter of the securing piece 37 to the diameter of the throughopening 40 so that before the mounting of the pump housing 10 onto themotor housing 45′, the pump shaft 14 or 14′ can be supported at thethrough opening 40 by way of the circumferential securing piece 37. Inthis variant, the through opening 40 is used as a support face 42′provided directly on the pump housing 10 (FIG. 5). The support face 42or 42′ is therefore respectively connected at least indirectly to thepump housing 10.

There is a diametrical difference, i.e. a radial distance, between thesupport face 42 or 42′ and the region of the pump shaft 14 or 14′, whichrests against the support face 42, 42′ before the mounting of the pumphousing 10 onto the motor housing 45′, wherein the distance isdimensioned so that as soon as the pump is mounted onto the motorhousing 45′, the pump shaft 14, 14′ cannot touch the support face 42 or42′, independent of possibly occurring radial runout of the shaft 46.

The foregoing relates to a preferred exemplary embodiment of theinvention, it being understood that other variants and embodimentsthereof are possible within the spirit and scope of the invention, thelatter being defined by the appended claims.

What is claimed is:
 1. A high-pressure pump for a fuel injection deviceof an internal combustion engine, comprising a pump housing, with atleast one work chamber disposed in the pump housing functionally betweenan inlet region and a supply region, a working element is movablydisposed in said at least one work chamber, a pump shaft provided in thepump housing by means of which the at least one working element isdriven, for use, the pump housing (10) is fastened to a wall (45) of ahousing (45′) of the internal combustion engine, wherein in use the pumpshaft (14, 14′) is radially supported by a bearing-drive means driven byrotation of a shaft (46) of the internal combustion engine, said shaftis (46) rotated in and supported by bearing means in the internalcombustion engine housing (45′).
 2. The pump according to claim 1, inwhich a transport securing device (33, 42, 42′, 38, 39; 33, 56, 38, 39)is provided for securing the pump shaft (14; 14′) in place in the pumphousing said transport securing device holds the pump shaft (14; 14′)essentially in an operating position during a time period in which thepump housing (10) is not mounted to the housing (45′) of the internalcombustion engine.
 3. The pump according to claim 2, in which thetransport securing device includes first and second securing means (42,42′; 56 or 39), which are spaced apart from one another in a directionof a longitudinal axis of the pump shaft (14, 14′).
 4. The pumpaccording to claim 3, in which the first securing means (42, 42′; 56)supports the pump shaft (14; 14′) in a through opening (40) provided inthe pump housing (10), while the second securing means (39) is engagedby an auxiliary pin (38) connected to a cam (31) of the pump shaft (14;14′) inside the pump housing.
 5. The pump according to claim 1, in whichwith a cam (31) drive-side end, the pump shaft (14,14′) is guided in aseal (43) in a through opening (40) provided in the pump housing (10).6. The pump according to claim 5, in which the pump shaft (14; 14′) hasa sealing collar (33) thereon that cooperates with said seal (43; 56)that encompasses the pump shaft (14; 14′) in order to seal the pumphousing (10) in the through opening for the pump shaft (14; 14′).
 7. Thepump according to claim 6, in which a support face (42, 42′) thatencompasses the pump shaft (14, 14′) is provided at least indirectly inthe pump housing (10) and a diameter of the support face is greater thana corresponding diameter of the pump shaft (14, 14′).
 8. The pumpaccording to claim 6, in which the seal (43) encompassing the pump shaft(14; 14′) has a sealing lip (44) disposed on a radial inside of saidseal (43), said sealing lip (44) rests with an inner circumferenceagainst the sealing collar (33) and an inner diameter of said sealinglip (44) is smaller than an outer diameter of the sealing collar (33).9. The pump according to claim 6, in which an axially movable pressing,sealing ring (59) is disposed on the sealing collar (33) of the pumpshaft (14′) and with an end face (65), said sealing ring is pressedagainst a radially stationary slide face (66), which is provided on aslide ring (62) that is inserted into the through opening (40) for thepump shaft (14′) and is axially fixed at least in one direction.
 10. Thepump according to claim 6, in which on a side of the sealing collar (33)associated with the pump housing (10), the pump shaft (14, 14′) supportsa securing piece (37) that protrudes radially outward beyond the sealingcollar (33).
 11. The pump according to claim 6, in which the seal (43;56) encompassing the pump shaft (14; 14′) includes or constitutes afirst securing means (42; 56).
 12. The pump according to claim 1, inwhich the pump shaft (14, 14′) includes a bearing pin (34) whichprotrudes from the pump housing (10) and engages a corresponding axialbearing bore (47) in the shaft (46) of the internal combustion engine.13. The pump according to claim 1, in which a catch means (36; 55) isprovided on the pump shaft (14; 14′), and when the pump is mounted tothe internal combustion engine, said catch means engages at least onecatch (49) provided on an engaging end of the shaft (46) of the internalcombustion engine.
 14. The pump according to claim 13, in which a catchpin (55) that extends lateral to the pump shaft (14′) is provided as acatch means, and said catch pin (55) protrudes outward beyond the outercircumference of the bearing pin (34).
 15. The pump according to claim14, in which the catch pin (55) extends lateral to the pump shaft (14′)through a corresponding lateral bore (54) and protrudes outward beyondthe sealing collar (33) on at least one side.
 16. The pump according toclaim 1, in which for the alignment of the pump shaft (14, 14′) in thepump housing (10), said pump housing is provided with a centering means(41), which is aligned with a through opening (40) for the pump shaft(14, 14′) and cooperates with a corresponding centering means (48) thatsurrounds the shaft (46) of the internal combustion engine and isdisposed on the wall (45) of the motor housing (45′).
 17. The pumpaccording to claim 16, in which said centering collar (41) encompassesthe through opening (40) for the pump shaft (14, 14′) and is insertedinto a receiving bore (48) in the wall (45) of the motor housing (45′),said centering collar in said receiving bore serves as a centering meansand is coaxial to the shaft (46) of the internal combustion engine. 18.The pump according to claim 16, in which the pump shaft (14, 14′) has asupport means (38) on a cam end inside the housing of the pump shaftthat cooperates with a second securing means (39) disposed on the pumphousing (10), wherein the second securing means (39) is aligned coaxialto the centering means (41).
 19. The pump according to claim 18, inwhich as a support means, the pump shaft (14, 14′) has an auxiliary pin(38) that is coaxial to a bearing pin (34) and engages an auxiliary bore(39) of the pump housing with a radial clearance therebetween and saidbore (39) is coaxial to the centering means (41) and is used as thesecond securing means.
 20. The pump according to claim 19, in which theauxiliary pin (38) is supported in the auxiliary bore (39).
 21. The pumpaccording to claim 19, in which a disk (67), which is used as an axialbearing, is inserted into the auxiliary bore (39) and is comprised of alow-friction slide bearing material.